Systems and methods for responding to natural language speech utterance

ABSTRACT

Systems and methods are provided for receiving speech and non-speech communications of natural language questions and/or commands, transcribing the speech and non-speech communications to textual messages, and executing the questions and/or commands. The invention applies context, prior information, domain knowledge, and user specific profile data to achieve a natural environment for one or more users presenting questions or commands across multiple domains. The systems and methods creates, stores and uses extensive personal profile information for each user, thereby improving the reliability of determining the context of the speech and non-speech communications and presenting the expected results for a particular question or command.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.12/617,506, entitled “Systems and Methods for Responding to NaturalLanguage Speech Utterance,” filed Nov. 12, 2009, which is a continuationof U.S. patent application Ser. No. 11/197,504, entitled “Systems andMethods for Responding to Natural Language Speech Utterance,” filed Aug.5, 2005, which issued as U.S. Pat. No. 7,640,160 on Dec. 29, 2009, thecontents of which are hereby incorporated by reference in theirentirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to retrieval of information or processing ofcommands through a speech interface and/or a combination of a speechinterface and a non-speech interface. More specifically, the inventionprovides a fully integrated environment that allows users to submitnatural language questions and commands via the speech interface and thenon-speech interface. Information may be obtained from a wide range ofdisciplines, making local and network inquiries to obtain theinformation and presenting results in a natural manner, even in caseswhere the question asked or the responses received are incomplete,ambiguous or subjective. The invention may further allow users tocontrol devices and systems either locally or remotely.

2. Background of the Related Art

A machine's ability to communicate with humans in a natural mannerremains a difficult problem. Cognitive research on human interactionshows that verbal communication, such as a person asking a question orgiving a command, typically relies heavily on context and domainknowledge of the target person. By contrast, machine-based queries(e.g., questions, commands, requests, and/or other types ofcommunications) may be highly structured and may not be inherentlynatural to the human user. Thus, verbal communications and machineprocessing of queries taken from the verbal communications may befundamentally incompatible. Yet the ability to allow a person to makenatural language speech-based queries remains a desirable goal.

Speech recognition has steadily improved in accuracy and today issuccessfully used in a wide range of applications. Natural languageprocessing has been applied to the parsing of speech queries. Yet,current systems do not reliably provide a complete environment for usersto submit verbal and/or textual communications through natural languagequeries that are processed to provide natural responses. There remain anumber of significant barriers to creation of a complete speech-basedand/or non-speech-based natural language query and response environment.

SUMMARY OF THE INVENTION

According to an aspect of the invention, one object of the invention isto overcome these and other drawbacks of prior systems.

According to one aspect of the invention, users may provide the systemwith spoken utterances and/or textual communications in a naturallanguage format, including imperfect information such as, incompletethoughts, incomplete sentences, incomplete phrases, slang terminology,repeated words, word variations, synonyms, or other imperfectinformation. In order for machines (e.g., computer devices) to properlyrespond to questions and/or commands that are presented in the naturallanguage format, the questions and/or commands may be parsed andinterpreted to formulate machine processable queries and algorithms.

In another aspect of the invention, systems are provided for overcomingthe deficiencies of prior systems through the application of a completespeech-based information query, retrieval, presentation and commandenvironment or a combination of speech-based and non-speech-basedinformation query, retrieval, presentation and command environment. Thisenvironment makes maximum use of context, prior information, domainknowledge, and user specific profile data to achieve a naturalenvironment for one or more users submitting queries or commands tomultiple domains. Through this integrated approach, a completespeech-based natural language query and response environment may becreated. Alternatively, a combination of speech-based andnon-speech-based natural language query and response environment may becreated. Further, at each step in the process, accommodation may be madefor full or partial failure and graceful recovery. The robustness topartial failure is achieved through the use of probabilistic and fuzzyreasoning at several stages of the process. This robustness to partialfailure promotes the feeling of a natural response to questions andcommands.

According to another aspect of the invention, the system may include aspeech unit interface device that receives utterances, including spokennatural language queries, commands and/or other utterances from a user,and a computer device or system that receives input from the speech unitand processes the input (e.g., retrieves information responsive to thequery, takes action consistent with the command and performs otherfunctions as detailed herein). The system may further generate a naturallanguage response and/or generate a natural language message, such as analert message, without any prompting from a user. According to anotherembodiment of the invention, the non-speech interface may be provided inaddition to, or in place of, the speech unit interface. For example, thenon-speech interface may communicate non-speech information, such astextual communications, graphical or tabular information, or othernon-speech information.

According to one embodiment of the invention, infrastructure may beprovided to maintain context information during multi-modalinteractions, such as speech and/or non-speech interactions. Accordingto one exemplary embodiment of the invention, context information may bemaintained in a multi-modal environment by providing communicationchannels between multi-modal devices, or mobile device, and the system.The communication channels allow the system to receive multi-modal inputsuch as text-based commands and questions and/or voice commands andquestions. According to another embodiment of the invention, themulti-modal input may include a string of text, such as keywords, thatare received as commands or questions. According to yet anotherembodiment of the invention, the system may synchronize the contextbetween the multi-modal devices and the speech-based units. In order tosend a response to the corresponding device, the system may track thesource and send the response to the corresponding speech interface orthe non-speech interface.

According to an alternative embodiment of the invention, contextinformation may be maintained using a context manager that may becentrally positioned to receive input from multiple sources and toprovide output to multiple sources. According to one embodiment, thedevices that communicate with the context manager may register through aregistration module and may subscribe to one or more events. Accordingto another embodiment of the invention, the context manager may receiveinput in Context XML form, for example. The other registered devices maybe informed of context changes through a context tracking module toenable synchronizing of context across the registered modules. Accordingto one embodiment of the invention, registered modules may be added orremoved from the system. The registered modules may include dynamic linklibraries (DLLs) that are specific to multi-modal devices.

According to yet another alternative embodiment of the invention,context information may be determined from a command or request that ispresented in a textual format and/or a command or request that ispresented as an utterance and processed using a multi-pass automaticspeech recognition module that transcribes the utterance to a textmessage. The command or request may be compared against a contextdescription grammar to identify a match. Any active grammars in thecontext description grammar may be scored against the command or requestand a best match may be sent to a response generator module. Agents maybe associated with corresponding response generator modules and mayretrieve the requested information for generation of a response. Theagents may update a context stack to enable follow-up requests.

According to another aspect of the invention, the speech unit and/ormulti-modal device may be incorporated into the computer device orsystem, or may be separate structures. If separate structures areprovided, the speech unit and/or multi-modal devices may be connected tothe computer device via a wired or wireless connection. If a wirelessconnection is provided, a base unit may be connected to the computer,internally or externally, to communicate with the speech unit and/ormulti-modal device.

According to another aspect of the invention, the computer devices orsystems may comprise stand alone or networked PCs, personal digitalassistants (PDAs), cellular telephones, or other computer devices orsystems. For convenience, these and other computer alternatives arereferred to as computers. One aspect of the invention comprises softwarethat may be installed onto the computer, where the software may includeone or more of the following modules: a non-speech information receivingmodule; a speech recognition module that captures user utterances; aparser that parses the utterance; a text to speech engine module thatconverts the text to speech; a network interface that enables thecomputer to interface with one or more networks; a non-speech interfacemodule; and an event manager for managing events. Preferably, the eventmanager is in communication with a context description grammar, a userprofile module that enables user profiles to be created, modified andaccessed, a personality module that enables various personalities to becreated and used, an agent module, an update manager, a cognitive modelthat provides statistical abstracts of user interaction patterns withthe system, one or more databases, and other components.

According to another aspect of the invention domain specific behaviorand information may be organized into data managers. Data managers areautonomous executables that receive, process, and respond to userquestions, queries and commands. The data managers provide complete,convenient and re-distributable packages or modules of functionality,typically for a specific domain or application. Data managers may becomplete packages of executable code, scripts, links to information, andother forms of communication data that provide a specific package offunctionality, usually in a specific domain. In other words, datamanagers include components for extending the functionality to a newdomain. Further, data managers and their associated data may be updatedremotely over a network as new behavior is added or new informationbecomes available. Data managers may use system resources and theservices of other, typically more specialized, data managers. Datamanagers may be distributed and redistributed in a number of waysincluding on removable storage media, transfer over networks or attachedto emails and other messages. An update manager may be used to add newdata managers to the system or update existing data managers.

According to another aspect of the invention, license managementcapabilities allowing the sale of data managers by third parties to oneor more users on a one time or subscription basis may be provided. Inaddition, users with particular expertise may create data managers,update existing data managers by adding new behaviors and information,and making these data managers for other users as agents.

In order to enhance the natural query and response environment, thesystem may format results to increase understandability to users.Formatting and presentation of results may be based on the context ofthe questions, the contents of the response being presented, the historyof the interaction with the user, the user's preferences and interestsand the nature of the domain. By contrast, rigid, highly formatted, orstructured presentation of results may be deemed unnatural by manyusers.

According to another embodiment of the invention, the system maysimulate some aspects of a human “personality.” In some cases, thepresentation of the response and the terms that are used to provide theresponse may be randomized to avoid the appearance of rigidly formattedor mechanical responses. The use of other simulated personalitycharacteristics is also desirable. For example, a response that may beupsetting to the user may be presented in a sympathetic manner.Furthermore, results of requests may be long text strings, lists, tablesor other lengthy sets of data. Natural presentation of this type ofinformation presents particular challenges because simply reading thelong response is generally not preferred. Instead, the system may parseimportant sections from the response and may initially provide onlyreports. Determining what parts of a long response are presented may bebased on the context of the questions, the contents of the responsebeing presented, the history of the interaction with the user, theuser's preferences and interests and the nature of the domain. At thesame time, the system may give the user interactive control over whatinformation to present and how much information to present, to stop theresponse all together, or to take other actions.

According to another aspect of the invention, the system may process andrespond to questions, requests and/or commands. Keywords or context maybe used to determine whether the received utterance and/or textualmessage includes a request or command. For example, utterances mayinclude aspects of questions, requests and/or commands. For example, auser may utter “record my favorite TV program.” A request is processedto determine the name, the channel, and time for the user's favorite TVprogram. A command must be executed to set a video recorder to capturethis program.

For utterances including questions and/or requests, the system mayperform multiple steps that may include one or more of:

-   -   capturing the user's questions and/or requests through speech        recognition components that operate in a variety of real-world        environments;    -   parsing and interpreting the question and/or request;    -   determining the domain of expertise and context, invoking the        proper resources, including agents;    -   formulating one or more requests to one or more local and/or        network data sources or sending appropriate commands to local or        remote devices or the system itself;    -   performing presentation formatting, variable substitutions and        transformations to modify the requests to a form that yields        desired results from the available sources;    -   executing the multiple requests or commands in an asynchronous        manner and dealing gracefully with failures;    -   extracting or scraping the desired information from the one or        more results, which may be returned in any one of a number of        different formats;    -   evaluating and interpreting the results, including processing of        errors to provide one or more results judged to be “best,” even        if the results are ambiguous, incomplete, or conflicting;    -   performing formatting, variable substitutions and        transformations to modify the results to a form most easily        understood by the user; and    -   presenting the compound result, through a text to speech engine        or a multi-modal interface, to the user in a useful and expected        manner.

The above steps may be performed with knowledge of the domain ofexpertise, the context for the question or command, domain specificinformation, the history of the user's interactions, user preferences,available information sources or commands, and responses obtained fromthe sources.

Probabilistic or fuzzy set decision and matching methods may be appliedto deal with inconsistent, ambiguous, conflicting and incompleteinformation or responses. In addition, asynchronous queries may be usedto provide rapid and graceful failure of requests or commands that allowthe system to robustly return results quickly and in a manner that seemsnatural to the user.

Many everyday questions are inherently subjective and result in answersthat are a matter of opinion or consensus, as much as fact. Suchquestions are often ad hoc in their nature, as well. The system,according to another aspect of the invention, may use adaptive,probabilistic, and fuzzy set decision and matching methods to identifythe subjective nature of the question and to evaluate a range ofpossible answers, wherein one or more answers may be selected that mostaccurately represent the type of result desired by the user.

The context and expected results from a particular question may behighly dependent on the individual asking the question. Therefore, thesystem may create, store and use personal profile information for eachuser. Information in the profile may be added and updated automaticallyas the user uses the system or may be manually added or updated by theuser or by others. Domain specific agents may collect, store and usespecific profile information, as may be required for optimal operations.Users may create commands for regularly used reports, automaticallygenerated alerts, and other requests and for the formatting andpresentation of results. The system may use profile data in interpretingquestions, formulating requests, interpreting request results andpresenting answers to the user. Examples of information in a userprofile includes, history of questions asked, session histories,formatting and presentation preferences, special word spelling, terms ofinterest, special data sources of interest, age, sex, education,location or address, place of business, type of business, investments,hobbies, sports interests, news interests and other profile data.

According to one aspect of the invention, the system may attempt toprovide rapid responses in order to provide a natural question andresponse environment. The rapid responses may be provided withoutobtaining additional information. The system may determine agentcomposition, context and/or domain for a user's question or command, forexample, by using a real-time scoring system or other technique. Basedon this determination, the system may trigger one or more agents torespond to the user's question or command. The agents may make one ormore requests and rapidly return a formatted response. Thus, users mayreceive direct responses to a set of questions, each with a differentresponse or context. In some cases, the available information, includingthe request results, may not adequately answer the questions presented.In such situations, the user may be asked one or more follow-upquestions to resolve the ambiguity. Additional requests may then be madebefore an adequate response is provided. In these cases, the system mayuse context information, user profile information and/or domain specificinformation to minimize the interaction with the user required todeliver a response.

If the confidence level of the domain or context score is not highenough to ensure a reliable response, the system may request that theuser verify that the question or command is correctly understood. Ingeneral, the question may be phrased to indicate the context of thequestion including all criteria or parameters. If the user confirms thatthe question is correct, the system may proceed to produce a response.Otherwise, either the user can rephrase the original question, perhapsadding additional information to remove ambiguity, or the system may askone or more questions to attempt to resolve the ambiguity or otheractions may taken.

According to one aspect of the invention, the system may accept anynatural language question or command and, as a result, may be subject toambiguous requests. To assist users in formulating concise questions andcommands, the system may support a voice query language. The languagemay help users clearly specify the keywords or contexts of the questionor command along with the parameters or criteria. The system may providebuilt in training capabilities to help the user learn the best methodsto formulate their questions and commands.

In order to make the responses to user's questions and commands seemmore natural, the system may employ one or more dynamically invokablepersonalities and/or emotional models. Personalities and emotionalmodels have specific characteristics that simulate the behavioralcharacteristics of real humans. Examples of these characteristicsinclude sympathy, irritation, and helpfulness and associated emotions.The personality also randomizes aspects of responses, just as a realhuman would do. This behavior includes randomization of terms used andthe order of presentation of information. Characteristics of thepersonality and/or emotions are invoked using probabilistic or fuzzy setdecision and matching methods and using criteria, including the contextfor the question, the history of the user's interaction, userpreferences, information sources available, and responses obtained fromthe sources.

According to another aspect of the invention, special procedures may beemployed to present information in the form of long text strings,tables, lists or other long response sets. Simply presenting a long setof information in an ordered manner may not be considered natural orwhat most users have in mind. The system may use probabilistic or fuzzyset matching methods to extract relevant information and present thesesubsets first. Further the system may provide commands allowing users toskip through the list, find keywords or key information in the list orstop processing the list altogether.

In addition to the ability to process user questions and commands, theinvention may provide local or remote control functions for the systemor for other devices. Users may initiate commands locally or remotely.Several techniques for executing remote operations are possible, forexample, the use of a telephone or other audio connection. Other remotecommand techniques may be used. The processing of these commands may beperformed in a nearly identical manner to a question. One differencebeing that the result of the command is generally an action rather thana response. Examples of control operations supported by the inventioninclude, finding and playing music, film, games or other entertainmentmedia, control of the appliances or other electronic orelectro-mechanical devices, security systems control, audio, text andvideo conferencing (including Voice over IP conferencing), operatingintegrated messaging environments and other control operations.

By using an optional analog or digital telephone interface or a datanetwork interface, the invention can provide remote control capabilityof the computer or and auxiliary devices connected to the computer. Forexample, if the computer is connected via an interface to one or moreauxiliary devices, a remote user can use this capability to remotelycontrol or program the operation of the auxiliary device. For example,this enables recording of a television program, checking the status of ahome security system, checking voice mail messages, hearing andresponding to email messages, and much more. For each user commandutterance, the system may execute a number of steps possibly including:

-   -   capturing the user's command through speech recognition that        operates in a variety of real-world environments;    -   parsing and interpreting the command;    -   determining the domain for the command and context, invoking the        proper resources, including agents;    -   formulating device specific commands for the system or external        devices;    -   routing commands to the system, or external devices, including        external devices connected to data networks;    -   receiving and processing results of commands, including errors;        and    -   optionally, providing responses to users indicating the success        or failure of the command, and possibly including state        information.

The system may be used in conjunction with a wide range of platformenvironments. These environments may include, as a peripheral to a PC, aportable or wearable computer or other computer, embedded in a PC orother computer, on a personal digital assistant, such as a PDA withwireless networking capability, in a specialized device such as a barcode scanner or payment terminal, on a wireless telephone, or otherplatforms. If the invention is used with a mobile or portable devicethat has position location capability, the location data can be used bythe invention as part of the context for user questions. A user may usethe system on one or more devices. In this case, history and profileinformation for the user may be synchronized between the multipledevices on a periodic basis or other basis.

According to another aspect of the invention, the system may be deployedin a network of devices that use a common base of agents, data,information, user profiles and histories. Each user can then interactwith, and receive, the same services and applications at any locationequipped with the required device on the network. For example, multipledevices on which the invention is deployed, and connected to a network,can be placed at different locations throughout a home, place ofbusiness or other location. In such a case, the system may use thelocation of the particular device addressed by the user as part of thecontext for the questions asked.

According to one embodiment of the invention, the system may supportmultiple users that access the system at different times. According toanother embodiment of the invention, the system may support multipleusers that access the system during a same session in an interleaved oroverlapping manner. The system may recognize the multiple users by name,voice, or other characteristic and may invoke a correct profile for eachuser. If multiple users are addressing the system in overlapping orinterleaved sessions, the system may identify the multiple users and mayinvoke one or more corresponding profiles. For applications that requiresecurity safeguards, the multiple users may be verified using voiceprintmatching, password or pass-phrase matching, or other securitysafeguards.

When multiple users are engaged in interleaved sessions, the system maygracefully resolve conflicts using a probabilistic or fuzzy set decisionmethod for each user. This process may simulate the manner in which ahuman would address multiple questions from various sources. Forexample, the system may answer short questions first in time whileanswering longer questions later in time. Alternatively, the system mayanswer questions in the order that they are received, among otherconfigurations.

Given the desire for domain specific behavior, user specific behaviorand domain specific information, the system, according to another aspectof the invention, may allow both users and content providers to extendthe system capabilities, add data to local data sources, and addreferences to network data sources. To allow coverage of the widestpossible range of topics, the system may allow third party contentdevelopers to develop, distribute and sell specialized or domainspecific system programs and information. Content may be created thoughcreation of new data managers, scripting existing data managers, addingnew data to agents or databases and adding or modifying links toinformation sources. Distribution of this information is sensitive tothe user's interests and use history and to their willingness to pay ornot.

According to another aspect of the invention, the system may allow usersto disseminate their knowledge without programming. The system mayinclude mechanisms that allow users to post and distribute data managersand information in their particular areas of expertise, to improvesystem capability. Further, users can extend the system and configure itto their own preferences, add information to their profile to define newquestions or queries, extend and modify existing questions and queries,add new data sources, update data sources, set preferences and specifypresentation parameters for results.

Since the invention may operate in many environments, includingenvironments with background noise, point noise sources and peopleholding conversations, filtering of speech input may be performed. Theinvention may use, for example, either one-dimensional ortwo-dimensional array microphones to receive human speech. The arraymicrophones may be fixed or employ dynamic beam forming techniques. Thearray pattern may be adjusted to maximize gain in the direction of theuser and to null point noise sources. Speech received at the microphonesmay then be processed with analog or digital filters to optimize thebandwidth, cancel echoes, and notch-out narrow band noise sources.Following filtering, the system may use variable rate sampling tomaximize the fidelity of the encoded speech, while minimizing requiredbandwidth. This procedure may be particularly useful in cases where theencoded speech is transmitted over a wireless network or link.

Some example applications for the invention include, but are not limitedto, the following:

-   -   white pages and yellow pages lookups to find email addresses,        telephone numbers, street addresses and other information for        businesses and individuals;    -   personal address book, calendars and reminders for each user;    -   automatic telephone dialing, reading and sending emails and        pages by voice and other communications control functions;    -   map, location and direction applications;    -   movie or other entertainment locator, review information and        ticket purchasing;    -   television, radio or other home entertainment schedule, review        information and device control from a local or remote user;    -   weather information for the local area or other locations;    -   stock and other investment information including, prices,        company reports, profiles, company information, business news        stories, company reports, analysis, price alerts, news alerts,        portfolio reports, portfolio plans, etc.;    -   flight or other scheduled transportation information and        ticketing;    -   reservations for hotels, rental cars and other travel services;    -   local, national and international news information including        headlines of interest by subject or location, story summaries,        full stories, audio and video retrieval and play for stories;    -   sports scores, news stories, schedules, alerts, statistics, back        ground and history information, etc.;    -   ability to subscribe interactively to multimedia information        channels, including sports, news, business, different types of        music and entertainment, applying user specific preferences for        extracting and presenting information;    -   rights management for information or content used or published;    -   horoscopes, daily jokes and comics, crossword puzzle retrieval        and display and related entertainment or diversions;    -   recipes, meal planning, nutrition information and planning,        shopping lists and other home organization related activities;    -   interfaces to auctions and online shopping, and where the system        can manage payment or an electronic wallet;    -   management of network communications and conferencing, including        telecommunications, email, instant messaging, Voice over IP        communications and conferencing, local and wide area video and        audio conferencing, pages and alerts;    -   location, selection, management of play lists and play control        of interactive entertainment from local or network sources        including, video on demand, digital audio, such as MP3 format        material, interactive games, web radio and video broadcasts;    -   organization and calendar management for families, businesses        and other groups of users including the management of, meetings,        appointments, and events; and    -   interactive educational programs using local and network        material, with lesson material level set based on user's        profile, and including, interactive multimedia lessons,        religious instruction, calculator, dictionary and spelling,        language training, foreign language translation and        encyclopedias and other reference material.

It will be appreciated that the foregoing statements of the features ofthe invention are not intended as exhaustive or limiting, the properscope thereof being appreciated by reference to this entire disclosureand reasonably apparent variations and extensions thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described by reference to the preferred andalternative embodiments thereof in conjunction with the drawings inwhich:

FIG. 1 is an overall diagrammatic view according to one embodiment ofthe invention.

FIG. 2 is a schematic block diagram showing the agent architectureaccording to one embodiment of the invention.

FIG. 3 is a high level process for receiving natural languagespeech-based queries and/or commands and generating a response accordingto one embodiment of the invention.

FIG. 4A is a process for receiving natural language speech-based queriesand/or commands and generating a response according to one embodiment ofthe invention.

FIG. 4B is a process for receiving natural language speech-basedcommands in order to locally or remotely control functions of devicesaccording to one embodiment of the invention.

FIG. 5 is a process for correctly interpreting a user's utteranceaccording to one embodiment of the invention.

FIG. 6 is a process for determining the proper domain agents to invokeand the properly formatted queries and/or commands that is to besubmitted to the agents according to one embodiment of the invention.

FIG. 7 illustrates a diagram for centrally maintaining context,according to one embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Barriers to natural human request-response interaction between humansand machines include that natural language queries may be incomplete intheir definition. Furthermore, context of previous questions, knowledgeof the domain, and/or the user's history of interests and preferencesmay be needed to properly interpret questions and/or commands. Thus,natural language questions may not be easily transformed to machineprocessable form. Compounding this problem, natural language questionsmay be ambiguous or subjective. In these cases, forming a machineprocessable query and returning a natural language response may bedifficult.

In order for machines (e.g., computer devices) to properly respond toquestions or commands that are submitted in a natural language form,machine processable queries and algorithms may be formulated after thenatural form questions or commands have been parsed and interpreted.Algorithms describe how the machines should gather data to respond tothe questions or commands. Depending on the nature of the questions orcommands, there may not be a simple set of queries and algorithms thatwill return an adequate response. Several queries and algorithms mayneed to be initiated and even these queries and algorithms may need tobe chained or concatenated to achieve a complete response. Further, nosingle available source may contain the entire set of results needed togenerate a complete response. Thus, multiple queries and/or algorithms,perhaps with several parts, may be generated to access multiple datasources that are located either locally, remotely, or both. Not all ofthe data sources, queries and/or algorithms may return useful results orany results at all.

Useful results that are returned are often embedded in other informationand may need to be extracted from the other information. For example, afew keywords or numbers may need to be “scraped” from a larger amount ofother information in a text string, table, list, page, video stream orother information. At the same time, extraneous information includinggraphics or pictures may be removed to process the response. In anycase, the multiple results must be evaluated and combined to form thebest possible response, even in cases where some queries do not returnuseful results or fail to produce results entirely. In cases where thequestion is determined to be ambiguous or the result is inherentlysubjective, determining the results to present in the response is acomplex process. Finally, to maintain a natural interaction, responsesneed to be returned rapidly to the user. Managing and evaluating complexand uncertain queries, while maintaining real-time performance, is asignificant challenge.

The following detailed description refers to the accompanying drawings,and describes exemplary embodiments of the invention. Other embodimentsare possible and modifications may be made to the exemplary embodimentswithout departing from the spirit, functionality and scope of theinvention. Therefore, the following detailed descriptions are not meantto limit the invention.

The invention provides a complete speech-based information query,retrieval, processing, and presentation environment or a combination ofspeech-based and non-speech-based information query, retrieval,processing, and presentation environment. In addition, the invention maybe useful for controlling the system itself and/or external devices.This integrated environment makes maximum use of context, priorinformation and domain and user specific profile data to achieve anatural environment for one or more users submitting requests orcommands in multiple domains. Through this integrated approach, acomplete speech-based natural language query, algorithm and responseenvironment or a combination of speech-based and non-speech-based may becreated. FIG. 1 shows one exemplary schematic diagram view of a system90 according to an embodiment of the invention.

The system 90 may include a main unit 98, a speech unit 128, andmulti-modal device 155. Alternatively, the system 98 may comprisecompletely separate systems for main unit 98, speech unit 128 andmulti-modal device 155. The event manager 100 may mediate interactionsbetween other components of the main unit 98. The event manager 100provides a multi-threaded environment allowing the system 98 to operateon multiple commands or questions from multiple user sessions, withoutconflict, and in an efficient manner, maintaining real-time responsecapabilities.

Agents 106 may include a collection of grammars, criteria handlers, andalgorithms that are accessed to respond to a set of requests and/orcommands. Agents 106 further may contain packages of both generic anddomain specific behavior for the system 98. Agents 106 may usenonvolatile storage for data, parameters, history information, andlocally stored content provided in the system databases 102 or otherlocal sources. One or more user profiles 110 may be provided thatincludes user specific data, parameters, and session and historyinformation for determining the behavior of agents 106. One or morepersonality modules 108 may be provided in a data determining systemthat includes personality characteristics for agents 106. The updatemanager 104 manages the automatic and manual loading and updating ofagents 106 and their associated data from the Internet 146 or othernetwork through the network interface 116.

According to one embodiment of the invention, the speech-based interfacefor the system 90 may include one or more speech units 128. Speech units128 may include one or more microphones, for example array microphone134, to receive the utterances from the user. The speech received at themicrophone 134 may be processed by filter 132 and passed to the speechcoder 138 for encoding and compression. In one embodiment, a transceivermodule 130 transmits the coded speech to the main unit 98. Coded speechreceived from the main unit 98 is detected by the transceiver 130, thendecoded and decompressed by the speech coder 138 and annunciated by thespeaker 136.

According to one embodiment of the invention, the non-speech-basedinterface for the system 90 may include one or more multi-modal devices155 that may include mobile devices, stand alone or networked computers,personal digital assistances (PDAs), portable computer devices, or othermulti-modal devices.

The speech units 128, multi-modal devices 155 and the main unit 98 maycommunicate over a communication link. The communication link mayinclude a wired or wireless link. According to one embodiment, thecommunication link may comprise an RF link. The transceiver 130 on thespeech unit may communicate coded speech data bi-directionally over thecommunication link with the transceiver 126 on the main unit 98.According to another embodiment, RF link may use any standard local areawireless data protocols including the IEEE 802.11, Bluetooth or otherstandards. Alternatively, an infrared data link conforming to anysuitable standard such as IrDA or other infrared standards can be used.In an alternative embodiment, wires connect the speech unit 128 and themain unit 98, eliminating the need for one speech coder 138. Other wiredor wireless analog or digital transmission techniques can be used.

According to one embodiment of the invention, coded speech received atthe transceiver 126 on the main unit 98 may be passed to the speechcoder 122 for decoding and decompression. The decoded speech may beprocessed by the speech recognition engine 120 using the contextdescription grammar module 112, among other information. Any recognizedinformation may be processed by the parser 118, which transformsinformation into complete algorithms and questions using data suppliedby knowledge agents. Knowledge agents may be selected from the pluralityof agents 106 using a grammar stack, wherein the knowledge agentsprovide information for generating a response to the question orcommand. The knowledge agents may then process the commands or questionsby creating queries that are submitted to local databases 102 orsubmitted through the network interface 116 to external data sourcesover the Internet 146 or external other networks. Algorithms typicallyresult in actions taken by the system 90 itself (i.e., pause or stop),or to a remote device or data source (i.e., download data or program, orcontrol a remote device), through the network interface to the Internetor other data interface.

According to one embodiment of the invention, knowledge agents mayreturn results of questions as responses to users. The responses may becreated using the results of information queries, the system personality108, the user preferences, other data in the user profile 110, and/orother information. Agents 106 may present these results using the speechunit 128. The agents 106 may create a response string, which is sent tothe text to speech engine 124. The text to speech engine 124 generatesthe utterances, which may be encoded and compressed by the speech coder122. Once coded, the utterances are transmitted from the main unit 98 bythe transceiver 126 to the transceiver 130 on the speech unit 128. Theutterance is then decoded and decompressed by the speech coder 138 andoutput by the speaker 136. Alternatively, agents 106 may present theresults using multi-modal devices 155.

The non-speech interface 114 may be part of, or separate from, themulti-modal devices 155 and may be used as a substitute or maycomplement the speech interface. For example, non-speech interface 114may be used to present and to interact with non-speech (e.g., graphicalor tabular) information in a manner more easily digested by the user.According to one embodiment of the invention, multi-modal support may beprovided to maintain the context during both voice interaction andinteraction through the non-speech interface 114. In one exemplaryembodiment, a communication channel may be opened between multi-modaldevices 155 and the main user interface system 90 to allow multi-modaldevices 155 to input text commands and questions. The multi-modaldevices 155 may receive and/or provide one or more types ofcommunications including speech, text, digital audio files, and othercommunications. According to another embodiment of the invention,multi-modal devices 155 may send a string of text or keywords for acommand or question. The main interface system 90 may synchronize thecontext between multi-modal device 155 and the speech units 128. Inorder to send a response to the corresponding device, the main userinterface system 90 may track where the input came from so that theresponse may be sent to a TTS or multi-modal device 155.

According to an alternative embodiment of the invention illustrated inFIG. 7, a context manager 702 may be centrally maintained to allow inputfrom and output to multiple mobile devices 36. Each of the mobiledevices may communicate with the context manager 702 to register viaregistration module 712, wherein registration may indicate events thatthe mobile devices 36 may subscribe to. The context manager 702 mayreceive input in Context XML form, for example. The other registeredmobile devices 36 may be informed of a context changes through contexttracking module 714, thereby synchronizing the context across theregistered mobile devices 36. According to one embodiment of theinvention, registered mobile devices 36 may be added or removed. Theregistered mobile devices 36 may be dynamic link libraries (DLLs) thatmay be specific to the mobile devices 36.

According to yet another alternative embodiment of the invention,context information may be determined from a command or request that ispresented as a text message and/or a command or request that ispresented as a verbal utterance and processed using a multi-passautomatic speech recognition module that transcribes the verbalutterance to a text message. The multi-pass automatic speech recognitionmodule may use a dictation grammar or a large vocabulary grammar, amongother resources, to transcribe the verbal utterance into a text message.On platforms where a dictation grammar is not available, the multi-passautomatic speech recognition module may use a virtual dictation grammarthat uses decoy words for out-of-vocabulary words. Decoy words mayinclude utility words, nonsense words, isolated syllables, isolateddistinct sounds and other decoy words.

According to one embodiment of the invention, the text message may besearched for a particular character, group of characters, word, group ofwords, and other text combinations. The text combination may be comparedagainst entries in a context description grammar that is associated witheach agent 106. If a match is identified between an active grammar inthe context description grammar and the command and/or request, then thematch may be scored. The agents 106 may be ranked based on thedetermined score. In generating an aggregate response from the one ormore responses received from the agents 106, the ordering of theresponses from the individual agents may be determined based on the rankof agents 106. The aggregate response may be generated by a responsegenerator module. Agents 106 may update a context stack that includes anordered list of command contexts, to enable follow-up requests.

According to another embodiment of the invention, if a match is notfound, or only a partial match is found, between the text message andactive grammars, then a knowledge-enhanced speech recognition system maybe used to semantically broaden the search. The knowledge-enhancedspeech recognition system may be used to determine the intent of therequest and/or to correct false recognitions. The knowledge-enhancedspeech recognition may access a set of expected contexts that are storedin a context stack to determine a most likely context. Theknowledge-enhanced speech recognition may use context specific matchersthat are able to identify context such as time, location, numbers,dates, categories (e.g., music, movies, television, addresses, etc.) andother context. The matching may be performed by comparing a character,group of characters, a word, group of words, and other textcombinations. Alternatively, or in addition to text based matching, thematching may be performed using phonetic matching, among othertechniques. The results of any match may be used to generate a commandand/or request that is communicated to agents 106 for additionalprocessing. According to one embodiment of the invention, non-speechinterface 114 may show system, state and history information in a moreconcise manner than is possible through the speech interface. Non-speechinterface 114 may be accessed to create or extend capabilities of agents106. These operations may include scripting of agents, adding data tothe agent or databases 102 used by the agent, adding links toinformation sources, among other operations.

According to another embodiment of the invention, system 90 may includedifferent types of agents 106. For example, generic and domain specificbehavior and information may be organized into domain agents. A systemagent, on the other hand, may provide default functionality and basicservices. The domain agents provide complete, convenient andre-distributable packages or modules for each application area. In otherwords, the domain agents include data that is needed to extend or modifythe functionality of the system 90 in a current or new domain. Further,domain agents and their associated data can be updated remotely over anetwork as new behavior is added or new information becomes available.Domain agents may use the services of other, typically more specializeddata managers and the system agent 150. Agents are distributed andredistributed in a number of ways including on removable storage media,transfer over networks or attached to emails and other messages. Theinvention may provide license management capability allowing the sale ofdata managers by third parties to one or more users on a one time orsubscription basis. In addition, users with particular expertise maycreate data managers, update existing data managers by adding newbehaviors and information, and make these data managers to other usersas agents. A block diagram of an agent architecture according to anembodiment of the invention is shown in FIG. 2.

Agents 106 may receive and return events to the event manager 100. Bothsystem agents 150 and domain agents 156 may receive questions andcommands from the parser 118. Based on keywords in the questions andcommands and the structures of the questions and commands, the parsermay invoke selected agents. Agents use the nonvolatile storage for data,parameters, history information and local content provided in the systemdatabases 102.

According to one embodiment of the invention, when the system starts-upor boots-up, the agent manager 154 may load and initialize the systemagent 150 and the one or more domain agents 156. Agent manager 154includes knowledge of agents 106 and maps agents 106 to the agentlibrary 158. At shutdown, the agent manager may unload the agents 106.The agent manager 154 also performs license management functions for thedomain agents 156 and content in the databases 102.

The system agent 150 manages the criteria handlers 152 that handlespecific parameters or values (criteria) used to determine context forquestions and commands. According to one embodiment of the invention,criteria handlers 152 include parsing routines that are specialized torecognize particular parts of speech, such as times, locations, movietitles, and other parts of speech. The criteria handlers 152 mayidentify matching phrases and extract semantic attributes from thephrases. Both the system agent 150 and the domain agents 156 may use thecriteria handlers 152. The various domain agents 156 may use theservices of the system agent 150 and of other, typically morespecialized, domain agents 156. The system agent 150 and the domainagents 156 may use the services of the agent library 158, which containsutilities for commonly used functions. According to one embodiment ofthe invention, the agent library may be a dynamic link library thatimplements one or more agents. The agent library may include utilitiesfor text and string handling, network communications, database lookupand management, fuzzy and probabilistic evaluation, text to speechformats, and other utilities.

Domain agents 156 may be data-driven, scripted or created with compiledcode. A base of generic agent may be used as the starting point fordata-driven or scripted agents. Agents created with compiled code aretypically built into dynamically linkable or loadable libraries.Developers of agents can add new functionality to the agent library 158as required. Details of agent distribution and update, and agentcreation or modification are discussed in sections below.

According to another embodiment of the invention, capabilities areprovided to distribute and update system agents 150, domain agents 156,agent library 158 components, databases 102, and context descriptiongrammar 112 over wireless or wired networks 136, including dial-upnetworks using the update manager 104. The network interface 116 mayprovide connections to one or more networks. The update manager 104 mayalso manage the downloading and installation of core system updates. Theagent manager 154 may perform license management functions for thedomain agents and the databases. The update manager 104 and agentmanager 154 may perform these functions for all agents and databasecontent including, agents and content available to all users or agentsand/or content available to selected users. Examples of agent anddatabase components added or updated on a periodic basis include:

-   -   agents for new domains;    -   additional domain knowledge for agents;    -   new keywords for a domain, which can include names of        politicians, athletes, entertainers, names of new movies or        songs, etc. who have achieved recent prominence;    -   links to a preferred set of information sources for the domains        covered including links for, entertainment, news, sports,        weather, etc.;    -   updates to domain information based on, for example, changes to        tax laws, company mergers, changing political boundaries;    -   updates to content, including dictionaries, encyclopedias and        almanacs; and    -   other content and database components.

When a user requires or selects a new domain agent 156 or databaseelement 102, the update manager 104 may connect to their source on thenetwork 146 though the network interface 116, download and install theagent or data. To save system resources and to comply with any licenseconditions, the update manager 104 may uninstall agents that are nolonger in use. In one embodiment of the invention, the update manager104 may periodically query one or more sources of the licensed agentsand database components to locate and download updates to agentexecutables, scripts or data as they become available. Alternatively,the agent sources may initiate the downloading of agent updates of theregistered or licensed agents to the update manager as they becomeavailable.

The agent manager 154 may provide license management clients that arecapable of executing most any license terms and conditions. When aparticular agent 106 and/or database element 102 is selected based on asubmitted command, the agent manager 154 verifies that the use of theagent or data element is within the allowed terms and conditions, and ifso, invokes the agent or allows access to the data element. Licensemanagement schemes that can be implemented through the agent manager 154include outright purchase, subscription for updates, one time or limitedtime use. Use of shared agents and data elements (such as thosedown-loaded from web sites maintained by groups of domain experts) mayalso be managed by the agent manager 154.

If questions or commands do not match an agent that is currently loadedon the system, the agent manager 154 may search the network 146 throughthe network interface 116 to find a source for a suitable agent. Oncelocated, the agent can be loaded under the control of the update manager104, within the terms and conditions of the license agreement, asenforced by the agent manager.

New commands, keywords, information, or information sources can be addedto any domain agent 156 by changing agent data or scripting. Theseconfiguration capabilities may allow users and content developers toextend and modify the behavior of existing domain agents 156 or tocreate new domain agents 156 from a generic agent without the need tocreate new compiled code. Thus, the modification of the domain agents156 may range from minor data-driven updates by even the most casualusers, such as specifying the spelling of words, to development ofcomplex behavior using the scripting language as would typically be doneby a domain expert. The user can create and manage modifications todomain agents 156 through speech interface commands or using non-speechinterface 114. User-specific modifications of domain agents 156 arestored in conjunction with the user's profile 110 and accessed by thedomain agent 156 at run-time.

The data used to configure data driven agents 156 are structured in amanner to facilitate efficient evaluation and to help developers withorganization. These data are used not only by the agents 156, but alsoby the speech recognition engine 120, the text to speech engine 124, andthe parser 118. Examples of some major categories of data include:

-   -   1. Content packages include questions or commands. Each command        or question or group of commands or questions includes contexts        used for creation of one or more requests. The domain agent 156        passes a context description grammar expression to the parser        118 for evaluation of a context or question. An initial or        default context is typically supplied for each command or        question. The command or question may include a grammar for the        management and evaluation of the context stack.    -   2. Page lists or pointers to other local or network content        sources. For each page or content source, there is a pointer        (e.g., URL, URI, or other pointer) to the page or source. Each        page has specific scraping information used to extract the data        of interest. The scraping information includes matching        patterns, HTML or other format parsing information.    -   3. A response list, determining the response of the domain agent        156 to a particular command or question given the context, the        user profile and the information retrieved. Responses can        include diagnostic error messages or requests for more        information if the question or command cannot yet be resolved        from the known information. Responses can be based on or        dependent on thresholds or probabilistic or fuzzy weights for        the variables.    -   4. Substitution lists containing variable substitutions and        transformations, often applied by the agents 150, 156 in the        formatting of queries and results. For example, a stock domain        specific agent 156 would use a substitution list of company        trading symbols, company names and commonly used abbreviations.        Substitutions and transformations can be performed on commands        and questions to create precise queries, which can be applied        against one or more information sources or to results for        creating more meaningful output to the user. Substitution lists        also include information for optimally dealing with structured        information, such as HTTP formatted page parsing and evaluation.    -   5. Personalities used for responses. Personalities are        constructed by combining multiple traits in a weighted manner.        Weights can be specified for each agent's domain area to create        one or more specific personalities. Examples of personality        traits include sarcasm, humor, irritation, and sympathy, and        other traits.    -   6. Public and user specific parameters for sources,        substitutions, transformations, variables or criteria. The        public parameter lists are part of the agent package 156. The        user specific parameters are contained in the user profile 110.

Commands and questions are interpreted, queries formulated, responsescreated and results presented based on the users personal or userprofile 110 values. Personal profiles may include information specificto the individual, their interests, their special use of terminology,the history of their interactions with the system, and domains ofinterest. The personal profile data may be used by the agents 106, thespeech recognition engine 120, the text to speech engine 124, and theparser 118. Preferences can include, special (modified) commands, pastbehavior or history, questions, information sources, formats, reports,and alerts. User profile data can be manually entered by the user and/orcan be learned by the system 90 based on user behavior. User profilevalues may include:

-   -   spelling preferences;    -   date of birth for user, family and friends;    -   income level;    -   gender;    -   occupation;    -   location information such as, home address, neighborhood, and        business address;    -   car type;    -   telecommunications and other service providers and services;    -   financial and investment information;    -   synonyms (i.e., a nick name for someone);    -   special spelling;    -   keywords;    -   transformation or substitution variables;    -   domains of interest; and    -   other values.

End users may use the data driven agent 156 extension and modificationfacilities and values stored in user profiles 110 to create specialreports, packages of queries, alerts and output formats. A single alertor report can be configured to use multiple data sources, values, andother variable (i.e., time, location, etc.) to determine when alertsshould be sent. For example, an alert can be generated by sampling astock price every fifteen minutes and sending an alert if the pricedrops below some value. To create a report, the user first specifies aset of commands or questions. Next, the user creates or selects a formatfor the report. Finally the user may name the report. A report can havevariable parameters. For example, users may create a company stockreport, and execute the report by stating its name and the company name,which gives the user selected information and in a specified format forthat company. In another example, users can create a “morning” report,which presents selected multimedia information from different sources(e.g., news, sports, traffic, weather, etc.) in the order and formatsdesired. Alerts and reports can be created using only voice commands andresponses, commands and responses through non-speech interface 114, or acombination of the two. To create a report, alert, or other specializedbehavior, the user performs a number of steps including:

-   -   specify the command to run a report or alert;    -   specify the question or questions, including keywords, used for        a query;    -   set the criteria for running the report such as on command or        when a particular condition is met;    -   define preferred information sources;    -   define preferences for order of result evaluation by source,        value, etc.;    -   specify the presentation medium for a report or alert, such as        an email, the text to speech engine, a message to a pager, or a        text and graphics display; and    -   specify the preferred format for the report, such as information        to be presented, order of information to be presented, preferred        abbreviations or other variable substitutions.

Filtering and noise elimination may be important in facilitating thevarious functionalities of the system 90. Recognition and parsing of theuser's speech is implemented with good signal to noise ratio at theinput to the speech recognition engine 120. To provide acceptableresults, a set of acoustic models, an array microphone 134, a filter132, or other components, may be employed. If a good signal to noiseratio cannot be achieved, a noise identification algorithm may be usedand the appropriate acoustic model, for example, one that has beentrained in conditions similar to the identified noise, may be selected.According to an embodiment of the invention, the microphone array,filters and speech coder 138 are physically separated from the main unit98 into a speech unit 128, and connected using a wireless link. Sincebandwidth on a wireless connection is at a premium, the speech coderdynamically adapts the digitization rate and compression of the capturedspeech.

The speech unit 128 may use an array of microphones 134 to providebetter directional signal capture and noise elimination than can beachieved with a single microphone. The microphone array can beone-dimensional (a linear array) or two-dimensional (a circle, square,triangle or other suitable shape). The beam pattern of the array can befixed or made adaptive though use of analog or digital phase shiftingcircuitry. The pattern of the active array is steered to point in thedirection of the one or more users speaking. At the same time, nulls canbe added to the pattern to notch out point or limited area noisesources. The use of the array microphone also helps reduce the crosstalk between output from the text to speech engine 124 through thespeaker 136 and detection of the user's speech.

The microphone can be complemented with an analog or digital (i.e.,Voice over IP) speech interface. This interface allows a remote user toconnect to the system and interact with the system in the same mannerpossible if they were physically present.

The speech unit 128, according to an embodiment of the invention, mayuse an analog or digital filter 132 between the array microphone 134 andthe speech coder 138. The pass band of the filter is set to optimize thesignal to noise ratio at the input to the speech recognition engine 120.In some embodiments, the filter is adaptive, using band shaping combinedwith notch filtering to reject narrow-band noise. In one embodiment ofthe invention, the system 90 may employ adaptive echo cancellation inthe filter. The echo cancellation helps prevent cross talk betweenoutput from the text to speech engine and detection of the user's speechas well as suppression of environmentally caused echoes. Calculationsare conducted for comparing the background noise to the signal receivedfrom the user's speech and optimizing the band-shaping parameters of theadaptive filter. Those skilled in the art will be familiar with multipletechniques used to construct suitable digital and analog filters.

The speech received by the array microphone 134 and passed through thefilter 132 may be sent to the speech digitizer or coder 138. The speechcoder 138 may use adaptive lossy audio compression to optimize bandwidthrequirements for the transmission of the coded speech to the speechrecognition engine 120 over a wireless link. The lossy coding may beoptimized to preserve only the components of the speech signal requiredfor optimal recognition. Further, the lossy compression algorithms thatmay be used may be designed to prevent even momentary gaps in the signalstream, which can cause severe errors in the speech recognition engine.The digitized speech may be buffered in the coder and the coder mayadapt the output data rate to optimize the use of the availablebandwidth. The use of the adaptive speech coder is particularlyadvantageous when a band-limited wireless link is used between the coderand the speech recognition engine.

In an alternative embodiment, the array microphone can be replaced by aset of physically distributed microphones or a headset worn by the user.The distributed microphones can be placed in different parts of a roomor in different rooms. The distributed microphones can create athree-dimensional array to improve signal to noise ratio. The headsetmay use a wireless or wired connection.

While the invention is intended to be able to accept most any naturallanguage question or command, ambiguity may be a problem. To assistusers formulate concise questions and commands, the system 90 maysupport a voice query language. The language is structured to allow avariety of queries with minimal ambiguity. Thus, the voice querylanguage helps users clearly specify the keywords or contexts of thequestion or command along with the parameters or criteria. The languageprovides a grammar to clearly specify the keyword used to determine thecontext and a set of one or criteria or parameters. A user asking aquestion or stating a command in the voice query language is nearlyalways guaranteed to receive a response.

The voice query language may be sensitive to the contents of the contextstack, wherein a context defines a set of questions that can beactivated or deactivated during a conversation. According to oneembodiment, each agent may designate one context to be the root contextthat defines base algorithms that the agent implements. Thus, follow-upquestions can be asked using an abbreviated grammar, since keywords andcriteria can be inherited from the context stack. For example, the usercan simply ask about another keyword if the criteria of the questionremain constant.

The system 90 may provide built in training capabilities to help theuser learn the best methods to formulate their questions and commands.The interactive training allows users to audibly or visibly see themachine interpretation of their queries and provides suggestions on howto better structure a query. Using the interactive training users canquickly become comfortable with the voice query language and at the sametime learn how to optimize the amount of information required with eachstep of a dialog.

The output of the speech coder 122 may be fed to the speech recognitionengine 120. The speech recognition engine 120 recognizes words andphrases, using information in the context description grammar 112, andpasses these to the parser 118 for interpretation. The speechrecognition engine 120 may determine the user's identity by voice andname for each utterance. Recognized words and phrases may be tagged withthis identity in all further processing. Thus, as multiple users engagein overlapping sessions, the tags added by the speech recognition engine120 to each utterance allows other components of the system 90 to tiethat utterance to the correct user and dialog. The user recognitioncapability may further be used as a security measure for applications,such as auctions or online shopping, where this is required. Voicecharacteristics of each user may be contained in the user profile 110.

According to one embodiment of the invention, users may start a dialogwith the system 90 when they first address it. This can be done byspeaking a generic word (“computer”) or addressing a specific name(“Fred”), which may be generally tied to a system personality 108. Oncethe user starts the dialog, it may be recognized by the speechrecognition engine 120, using unique characteristics of the user'sspeech. At the end of a dialog or to interrupt a dialog, the user mayutter a dismissal word (“good bye”).

According to another embodiment of the invention, the system 90 mayemploy a speech recognition engine 120 that gains improved wordrecognition accuracy using data from context description grammar 112,user profiles 110, and the agents 106, among other components. At thesame time, the fuzzy set possibilities or prior probabilities for thewords in the context description grammar may be dynamically updated tomaximize the probability of correct recognition at each stage of thedialog. The probabilities or possibilities may be dynamically updatedbased on a number of criteria including the application domain, thequestions or commands, contexts, the user profile and preferences, userdialog history, the recognizer dictionary and phrase tables, and wordspellings, among other criteria.

For uncommon words or new vocabulary words, a user may be given theoption to spell the words. The spelling may be done by saying the namesor the letters or using a phonetic alphabet. The phonetic alphabet canbe a default one or one of the user's choosing.

Alternatively, when a user submits a word that is not recognized at allor is not correctly recognized by the speech recognition engine 120 thenthe user may be asked to spell the word. The speech recognition engine120 determines this condition based on confidence level for the scoringprocess. The word may be looked up in a dictionary and the pronunciationfor the word is added to either the dictionary, the agent 106, or theuser's profile 110. The word pronunciation can then be associated withthe domain, the question, the context and the user. Through thisprocess, the speech recognition engine learns with time and improves inaccuracy. To assist users in spelling words, an individualized phoneticalphabet can be used. Each user can modify the standard phoneticalphabets with words, which they can remember more easily.

Once the words and phrases have been recognized by the speechrecognition engine 120, the tokens and user identification is passed tothe parser 118. The parser 118 examines the tokens for the questions orcommands, context and criteria. The parser 118 determines a context foran utterance by applying prior probabilities or fuzzy possibilities tokeyword matching, user profile 110, and dialog history. The context of aquestion or command determines the domain and thereby, the domain agent156, if any, to be evoked. For example, a question with the keywords“temperature” implies a context value of weather for the question. Theparser dynamically receives keyword and associated prior probability orfuzzy possibility updates from the system agent 150 or an already activedomain agent 156. Based on these probabilities or possibilities thepossible contexts are scored and the top one or few are used for furtherprocessing.

The parser 118 uses a scoring system to determine the most likelycontext or domain for a user's question and/or command. The score isdetermined from weighing a number of factors, including the user profile110, the domain agent's data content and previous context. Based on thisscoring, the system 90 invokes the correct agent. If the confidencelevel of the score is not high enough to ensure a reliable response, thesystem 90 may ask the user to verify whether the question and/or commandis correctly understood.

In general, the question that is asked by the system 90 may be phrasedto indicate the context of the question including all criteria orparameters. For example, the question can be in the form of: “Did Iunderstand that you want such-and-such?” If the user confirms that thequestion is correct, the system proceeds to produce a response.Otherwise, the user can rephrase the original question, perhaps addingadditional information to remove ambiguity, or the system can ask one ormore questions to attempt to resolve the ambiguity.

Once the context for the question or command has been determined, theparser 118 can invoke the correct agent 156, 150. To formulate aquestion or command in the regular grammar used by agents, the parser118 may determine required and optional values for the criteria orparameters. These criteria may have been explicitly supplied by the useror may need to be inferred. The parser 118 may make use of the criteriahandlers 152 supplied by the system agent 150. The criteria handlers 152may provide context sensitive procedures for extracting the criteria orparameters from the user's questions or commands. Some criteria aredetermined by executing algorithms in the agent, while others may bedetermined by applying probabilistic of fuzzy reasoning to tables ofpossible values. Prior probabilities or fuzzy possibilities andassociated values are received from a number of sources including thehistory of the dialog, the user profile 110, and the agent. Based onuser responses, the prior probabilities or fuzzy possibilities areupdated as the system learns the desired behavior. For a weathercontext, examples of criteria include, location, date and time. Othercriteria can include command criteria (i.e., yes/no, on/off, pause,stop), and spelling. Special criteria handlers are available from thesystem agent for processing lists, tables, barge-in commands, longstrings of text, and system commands.

The criteria handlers 152 operate iteratively or recursively on thecriteria extracted to eliminate ambiguity. This processing helps reducethe ambiguity in the user's question or command. For example, if theuser has a place name (or other proper noun) in their utterance, theparser 118 can use services of the domain agent 156 to look up tables inthe databases 102 for place names or can attempt to determine which wordis the proper noun from the syntax of the utterance. In another example,the user asks “what about flight one hundred and twenty too?” The parserand domain agent use flight information in the database and networkinformation along with context to determine the most plausibleinterpretation among; flight one-hundred and flight twenty also, flightone-hundred and flight twenty-two, flight one-hundred and twenty-two,and the like.

Once the context and the criteria are determined, the parser 118 mayform the question or command in a standard format or hierarchical datastructure used for processing by the agents 150, 156. The parser 118 mayfill in all required and some optional tokens for the grammar of thecontext. Often the tokens must be transformed to values and formsacceptable to the agents. The parser obtains the requiredtransformations from the agents, dialog history or user profile 110.Examples of transformations or substitutions performed by the parser ontokens include:

-   -   substituting a stock symbol for a company name or abbreviation;    -   substituting a numerical value for a word or words;    -   adding a zip code to an address; and    -   changing a place or other name to a commonly used standard        abbreviation.

The agents 150, 156 may receive a command or question once the parser118 has placed it in the required standard format. Based on the context,the parser 118 evokes the correct agent to process the question orcommand.

Commands can be directed to the system 90 or to an external entity.System commands are generally directed to the system agent 150. Commandsfor external entities are generally processed by a domain agent 156,which includes the command context and behavior for the external entity.

Specific questions are generally directed to one of the domain agents156. Based on the question or context and the parameters or criteria,the domain agent creates one or more queries to one or more local orexternal information sources. Questions can be objective or subjectivein nature. Results for objective questions can often be obtained bystructured queries to one or more local or network information sources.Even for objective questions, the system 90 may need to applyprobabilistic or fuzzy set analysis to deal with cases of conflictinginformation or incomplete information. Information to answer subjectivequestions is generally obtained by one or more ad-hoc queries to localor network data sources, followed by probabilistic or fuzzy setevaluation of the one results to determine a best answer.

Once the domain agent 156 has formulated the one or more queries, theymay be sent to local and/or network information sources. The queries areperformed in an asynchronous manner to account for the fact that sourcesrespond at different speeds or may fail to respond at all. Duplicatequeries are sent to different information sources to ensure that atleast one source responds with a useful result in a timely manner.Further, if multiple results are received in a timely manner, they canbe scored by the system to determine which data is most reliable orappropriate. Examples of data sources accommodated include, HTTP datasources, sources with meta-data in various formats including XML,entertainment audio, video and game files including MP3, databases usingquery languages and structured responses such as SQL, and other datasources.

The local information sources can be stored in one or more systemdatabases 102 or can be on any local data storage such as a set of CDsor DVDs in a player or other local data storage. Network informationsources can be connected to the Internet 136 or other network andaccessed through a series of plug-ins, adaptors, known as pluggablesources, in the network interface 116. The pluggable sources in thenetwork interface 116 may be capable of executing the protocols andinterpreting the data formats for the data sources of interest. Thepluggable sources may provide information, scraping data and proceduresfor each source to the domain agents 156. If a new type of data sourceis to be used, a new plug-in or adaptor can be added to the networkinterface 116.

The domain agent 156 evaluates the results of the one or more queries asthey arrive. The domain agent 156 scores the relevance of the resultsbased on results already received, the context, the criteria, thehistory of the dialog, the user profile 110 and domain specificinformation using probabilistic or fuzzy scoring techniques. Part of thedialog history is maintained in a context stack. The weight of eachcontext for the scoring is based on the relevance of one context toanother and the age of the contexts. Other scoring variables can beassociated through the context stack. Contexts can also be exclusive, sothat previous contexts have no weight in the scoring.

Based on the continuous scoring processes, the domain agent 156 maydetermine if a single best answer can be extracted. For most questions,the desired result has a set of tokens that must be found to formulatean answer. Once a value has been found for each of these tokens, theresults are ready for presentation to the user. For example, for aquestion on weather, the tokens can include the date, day of week,predicted high temperature, predicted low temperature, chance ofprecipitation, expected cloud cover, expected type of precipitation andother tokens. Results processed in this manner include error messages.For subjective questions, this determination is made by determining amost likely answer or answers, extracted by matching of the resultsreceived. If no satisfactory answer can be inferred from the results ofthe query, the agent can do one of the following:

-   -   1. Ask the user for more information, typically through the        speech interface, and based on the results obtained formulate        new queries. This approach is applied when an irresolvable        ambiguity arises in the formulation of a response.    -   2. Formulate new queries based on the results received from the        first set of queries. This approach is typically applied in        cases where the responses received do not contain all the        required information. Information sources to query can be        inferred from the results already obtained (i.e., links in an        HTML document) or from other sources. Using this approach one or        more sets of queries and responses can be chained without the        need for action by the user.    -   3. Wait for additional queries to return results.

In any case, the domain agent 156 may continue to make requests andevaluate results until a satisfactory response is constructed. In doingso, the agent can start several overlapping query paths or threads ofinquiry, typically mediated by the event manager 100. This technique,combined with the use of asynchronous queries from multiple datasources, provides the real-time response performance required for anatural interaction with the user.

The domain agent 156 may apply conditional scraping operations to eachquery response as it is received. The conditional scraping actionsdepend on the context, the criteria, user profile 110, and domain agentcoding and data. For each token to be extracted, scraping criteria 152may be created using the services of the system agent 150. The scrapingcriteria may use format specific scraping methods including, tables,lists, text, and other scraping methods. One or more scraping criteriacan be applied to a page or results set. Once additional results arereceived, the domain agent 156 can create new scraping criteria to applyto results already acquired. The conditional scraping process removesextraneous information, such as graphics, which need not be furtherprocessed or stored, improving system performance.

The domain agent 156 may strongly influence how the results arepresented. For instance, once the domain agent 156 has created asatisfactory response to a question, the agent 156 may format thatresponse for presentation. Typically, the domain agent 156 formats theresponse into the markup format used by the text to speech engine 124.The domain agent 156 may also format the result presentation usingavailable format templates and based on the context, the criteria, andthe user profile 110. Variable substitutions and transformations may beperformed by the agent 156 to produce a response best understood andmost natural to the user. Further, the order of presentation of tokensand the exact terminology used to create a more natural response to theuser may be varied by the agent 156. The domain agent 156 may alsoselect the presentation personality 108 to be used.

The domain agent 156 may select the presentation template, determineorder of presentation for tokens and determine variable substitutionsand transformations using probabilistic or fuzzy set decision methods.The template used to form the presentation can be from the domain agentitself or from the user profile 110. The user profile 110 can completelyspecify the presentation format or can be used to select and then modifyan existing presentation format. Selection and formatting ofpresentation templates can also depend on the presentation personalitymodules 108. At the same time, the characteristics of the personalityused for the response are dynamically determined using probabilities orfuzzy possibilities derived from the context, the criteria, the domainagent itself and the user profile 110.

The domain agent 156 may apply a number of transformations to the tokensbefore presentation to the user. These variable substitutions andtransformations are derived from a number of sources including, domaininformation carried by the agent, the context, the token values, thecriteria, the personality module 108 to be used, and the user profile110. Examples of variable substitutions and transformations include:

-   -   substitution of words for numbers;    -   substitution of names for acronyms or symbols (i.e., trading        symbols);    -   use of formatting information derived from the information        sources (i.e., HTML tags);    -   nature of the response including, text, long text, list, table;    -   possible missing information or errors;    -   units for measurement (i.e., English or metric); and    -   preferred terminology from the user profile 110 or presentation        personality 108.

The system 90, according to another embodiment of the invention, mayprovide special purpose presentation capabilities for long text strings,tables, lists and other large results sets. Domain agents 156 may usespecial formatting templates for such results. The system agent 150 mayprovide special criteria handlers 152 for presentation and user commandsfor large results sets. The presentation templates used by the domainagents 156 for large results sets typically include methods forsummarizing the results and then allowing the user to query the resultin more detail. For example, initially only short summaries such asheadlines or key numbers are presented. The user can then query theresults set further. The criteria handlers 152 provide users with thecapability to browse large results sets. Commands provided by thecriteria handlers 152 for large results sets include, stop, pause, skip,rewind, start, and forward.

Some information, in formats such as video, pictures and graphics, maybe best presented in a displayed format. The domain agents 156 may applysuitable presentation templates in these cases and present theinformation through the graphical user interface 114. The system agent150 provides special criteria handlers 152 for presentation and usercommands for display presentation and control.

FIG. 3 illustrates a high level process 300 for receiving naturallanguage speech-based queries and/or commands and generating a responseaccording to an embodiment of the invention. The process 300 comprisesof individual steps, several of which may be repetitive in order toaccommodate partial failures. The process 300 may begin when a user'sutterance is received and processed at 302. The user utterance may be aquery and/or a command and may be of a natural language speech-basedform. After receiving the natural language query and/or command, thequery and/or command may be processed so that the data is in a moremachine understandable format such as in a digital format. Once theutterance has been converted into an understandable format, theutterance may be processed so that at least an approximate meaning ofthe utterance can be determined at 304. This may be accomplished by, forexample, the use of stored dictionaries, phrases, user profiles, domainagent data, and other data. Based on the approximate meaning of theutterance, one or more correctly formatted queries and/or commands maybe generated.

A user created query and/or command may require that multiple requestsand/or commands may be needed in order to generate the desired responseor action. Further, depending upon the context in which the query and/orcommand has been submitted (e.g., who is the user, what is the subjectof the query and/or command directed to, at what time or location is thequery and/or command being directed to, and other parameters used indefining the query and/or command), a specific format for the queryand/or command may be required. For instance, each of the domain agents156 may require that requests and/or commands be formatted in a specificmanner. Thus at 306, one or more properly formatted queries and/orcommands may be generated. Operations 304 and 306 may be repeated inorder to obtain the correct interpretation of the user utterance andresult in the desired response and/or action. Once the properlyformatted queries and/or commands are generated, the appropriate actionmay be taken at 308. This may require that the properly formattedqueries and/or commands be sent to specific domain agent[s], informationsource[s], device[s], or other appropriate destination[s] that canfulfill the requirements of the query and/or command. Once theappropriate action[s] have been executed, this event may be recorded to,for example, the user's profile, database and/or one or more agents at310. Such data may be useful for future user inquires and commands.After the action[s] have been performed, a response, if need be, may begenerated and forwarded to the user and/or third parties at 312.

In the case of a query for retrieving data, the response would containthe requested information. In the case of a command, the response may bea confirmation that a specific action[s] has been executed. The responsemay be in the form of a natural language format. The response may alsobe formatted to reflect a particular personality or tone to the responsein order to make the response more “human.” The response may be relayedto the user and/or third parties as an audio message and/or a visualmessage displayed on a user interface.

FIG. 4A is a process 400 for receiving natural language speech-basedqueries and/or commands and generating a response using the system 90according to another embodiment of the invention. The process 400 maybegin when a user's utterance (i.e., user query and/or command) iscaptured through speech recognition operating in a variety of real-worldenvironments at 402. Once the utterance is captured, it is parsed andinterpreted to determine the query and/or command that is contained inthe utterance at 404. Next, the query and/or command are reviewed todetermine the domain of expertise required and the context of the query,invoking the proper resources including, for example, agents at 406. Theoriginal query and/or command submitted by the user may require thatmultiple queries and/or commands be generated.

For instance, suppose a user is interested in retrieving the value ofher stock portfolio. The user may utter “please get the value of mystock portfolio.” The system 90 may review this request together withstored data such as the user's profile and determine keywords such as“get the value” and “my stock portfolio.” The system 90 may thengenerate queries to determine the stocks in the user's portfolio, thenumber of shares and the source for current pricing information. Thesequeries may then be sent to one or more agent domains, such as a domainwhich may access a database containing the user's profile and a domainwhich accesses stock pricing sources to determine the answers to thesequestions.

Queries may be sent to these domain agents or sources in order to obtainthe desired data. Thus, at operation 408, one or more queries may beformulated and sent to one or more local and/or network data sourcesand/or appropriate commands may be sent to local or remote devices orthe system itself. The queries are then sent to the designated agent[s].The agents may then, in turn, generate their own queries and/or commandsto be sent to, for example, local or remote information sources toretrieve needed data. The agent generated queries and/or commands may beformatted according to the requirements of the target sources andvariable substitutions and transformations are performed to modify thequeries to a form most likely to yield desired results from theavailable sources at 410. Once the queries are formatted correctly, theymay be executed in an asynchronous manner and dealing gracefully withfailures at 412. As a result of the execution of the queries, resultsmay be returned by the domain agents and/or sources. The system 90 maythen extract or scrape the desired information from the one or moreresults, which may be returned in any one of a number of differentformats at 414. That is, the results sought by a user may be the summaryor the results of further processing of information obtained fromseveral sources for example.

Next, the results may be evaluated and interpreted including processingof errors, and gathering and combining them into a single best resultjudged to be “best” even if the results are ambiguous, incomplete, orconflicting at 416. Once the best results are determined, any requiredformatting is performed. At operation 418, variable substitutions andtransformations may be used to modify the results. Finally, at operation420, the compound results may be presented to the user in a useful andexpected manner through the text to speech engine 124. The process 400may be performed while accounting for the domain of expertise required,the context in which the question or command is presented, the domainspecific information available, the history of the user's interaction,the user preferences, the information sources or commands that areavailable, and responses obtained from the sources.

At each stage of the process 400, probabilistic or fuzzy set decisionand matching methods may be applied to deal with inconsistent,ambiguous, conflicting and incomplete information or responses. Inaddition, the use of asynchronous queries that may result in rapid andgraceful failure of some queries or commands may allow the system 90 torobustly return results quickly and in a manner that seems natural tothe user.

FIG. 4B illustrates a process 450 for receiving natural languagespeech-based commands in order to locally or remotely control functionsof the system 90, or for other devices, according to another embodimentof the invention. The process 450 may begin when a user's utterance(i.e., user query and/or command) is captured through speech recognitionoperating in a variety of real-world environments at 452. Once theutterance is captured, it is parsed and interpreted to determine thecommand that is contained in the utterance at operation 454.

Next, at operation 456, the command is reviewed to determine the domainfor the command and context and invoke the proper resources, includingagents. The original command submitted by the user will often requirethat multiple queries and/or commands be generated. For instance,suppose a user is interested in recording his favorite televisionprogram. The user may utter “please record my favorite TV program.” Thesystem 90 may review this request together with stored data such as theuser's profile and determine keywords such as “record” and “my favoriteTV program.” The system 90 may then generate queries to determine thename, the channel, and time for the user's favorite TV program. Thesequeries may then be sent to a domain agent, which may access a databasecontaining the user's profile and determine the answers to thesequestions. A command may then be sent to a video recorder ordering thevideo recorder to record the selected TV program. Thus, at operation458, one or more queries may be formulated that are to be sent to one ormore local and/or network data sources. Appropriate commands may be sentto local or remote devices or the system itself. Next, at operation 460,the generated commands may be routed to the appropriate system[s] and/orexternal devices. Once the commands have been executed, resultsincluding errors may be received and processed at 462. The results ofthe executed commands may be optionally presented to the user atoperation 464.

Some of the operations depicting in FIG. 4A may be performed usingmultiple steps that may be repetitive. For instance, in operation 404,the user's utterance is parsed and interpreted in order to determine themeaning of the utterance. System 90 may make an initial interpretationof the utterance based the data stored in, for example, the contextdescription grammar module 112, user profiles 110, agents 106 and thedatabases 102. A real-time scoring system or other techniques may beapplied to the interpretation results in order to generate a domain or acontext score. If the confidence level of the domain or context score isnot high enough to ensure a reliable response, the system 90 can requestthat the user verify the question or command is correctly understood. Ingeneral, the question may be phrased to indicate the context of thequestion including all criteria or parameters. If the user confirms thatthe question is correct, the system 90 may proceed to produce aresponse. Otherwise, either the user can rephrase the original question,perhaps adding additional information to remove ambiguity, or the systemmay ask one or more questions to attempt to resolve the ambiguity orother actions may taken.

FIG. 5 illustrates a process 500 for correctly interpreting a user'sutterance according to one embodiment of the invention. The process 500generally represents operations 402 and 404 of process 400. Initiallythe user's utterance is inputted into the system 90 at operation 502.The input is then interpreted at 504 using, for example, various sourcesof stored data such as user profiles, agent data, dictionary andphrases, and other relevant data. The interpretation is then scoredusing, for instance, a weighted scoring system as described previouslyat 506. Once a score is obtained, the confidence level of theinterpretation may be analyzed to determine if it is satisfactory atoperation 508. In other words, the determination relates to whether thescore given to the interpretation exceeds a certain value. If theconfidence level is determined to be unsatisfactory, then a request maybe submitted to the user requesting that the user verify theinterpretation at 510 and 512. If the user is unsatisfied with theinterpretation, he/she may be asked to rephrase the utterance and/orprovide additional information at 514. Once the user provides therephrased utterance and/or additional information, the process 500returns to the beginning at operation 502. If, on the other hand, theuser is satisfied with the interpretation, then the process 400 forreceiving natural language speech-based queries and/or commands, andgenerating a response, may continue at operation 516. Once the meaningof the utterance has been determined, the appropriate domain agent[s]and the query and/or commands properly formatted for the agent[s] may bedetermined.

FIG. 6 illustrates a process 600 for determining the proper domainagent[s] to invoke and the proper formatting of queries and/or commandsthat are submitted to the agents 106, as generally depicted in steps406-408 of FIG. 4A. In order to formulate a question or command in theregular grammar used by agents 106, a determination may be made as tothe required and optional values for the criteria or parameters of thequeries and/or commands. These criteria may have been explicitlysupplied by the user or may need to be inferred. Thus, the properlyinterpreted query and/or command that is generated by, for example,operations 404 and 454 of FIGS. 4A and 4B, is parsed at operation 602.

The content of the properly interpreted query and/or command is thenanalyzed to determine the criteria and/or parameters of the properlyinterpreted query and/or command at 604. A context sensitive procedurefor extracting the criteria or parameters from the properly interpretedquery and/or command may be used. Some criteria are determined byexecuting algorithms in the agent, while others may be determined byapplying probabilistic of fuzzy reasoning to tables of possible values.Prior probabilities or fuzzy possibilities and associated values arereceived from a number of sources including the history of the dialog,the user profile 110, and the agent.

Based on user responses, the prior probabilities or fuzzy possibilitiesare updated as the system 90 learns the desired behavior. For a weathercontext, examples of criteria include, location, date and time. Othercriteria can include command criteria (i.e., yes/no, on/off, pause,stop), and spelling. The process for determining criteria may beiterative or recursive in order to eliminate ambiguity in the user'squestion or command. For example, if the user has a place name (or otherproper noun) in their utterance, tables in the databases 102 may bereviewed for place names or an attempt may be made to determine whichword is the proper noun from the syntax of the utterance. In anotherexample, the user asks “what about flight one hundred and twenty too?”In such a situation, flight information in the database and networkinformation along with context may be used to determine the mostplausible interpretation among flight one-hundred and flight twentyalso, flight one-hundred and flight twenty-two, flight one hundredtwenty-two, and the like. Once the parameters and criteria for the queryand/or command have been established, the proper agents 106 may beselected at 606.

After selecting the agents 106, at operation 608, a properly formattedquery and/or command that will be submitted to the agents 106 may bedetermined. The query and/or command may be in a standard format or maybe a hierarchical data structure used for processing by the agent 106.In order to submit the properly formatted query and/or command to theagent 106, all of the required, and some optional tokens, for thegrammar of the context may be filled in. Often the tokens must betransformed to values and forms acceptable to the agents. The requiredtransformations may be obtained from the agents, dialog history or userprofile 110. Examples of transformations or substitutions that may beperformed were provided above. Once the properly formatted queriesand/or commands are generated, the process (e.g., process 400) maycontinue at 610.

While specific embodiments of the invention have been described above,it will be appreciated that the invention may be practiced otherwisethan as described. For example, the invention may take the form of acomputer program containing one or more sequences of machine-readableinstructions describing a method as disclosed above, or a data storagemedium (e.g., semiconductor memory, magnetic or optical disk) havingsuch a computer program stored therein.

The descriptions above are intended to be illustrative, not limiting.Thus, it will be apparent to one skilled in the art that modificationsmay be made to the invention as described without departing from thescope of the claims set out below.

1-30. (canceled)
 31. A system for facilitating notification of contextchanges across multiple electronic devices, the system including one ormore processors executing one or more computer program modules which,when executed, cause the system to: register a library associated with afirst electronic device to subscribe the first electronic device to oneor more context events; receive a context change event from a secondelectronic device; and inform the first electronic device of the contextchange event to synchronize a context across the first electronic deviceand the second electronic device.
 32. The system of claim 31, whereinthe system is caused to: receive a subsequent context change event fromthe first electronic device; and inform the second electronic device ofthe subsequent context change event in response to the second electronicdevice having a subscription to the subsequent context change event. 33.The system of claim 31, wherein the system is caused to remove thelibrary to unsubscribe the first electronic device from the one or morecontext events.
 34. A method for facilitating notification of contextchanges across multiple electronic devices, the method being implementedin a computer system that includes one or more processors executing oneor more computer program modules which, when executed, perform themethod, the method comprising: registering a library associated with afirst electronic device to subscribe the first electronic device to oneor more context events; receiving a context change event from a secondelectronic device; and informing the first electronic device of thecontext change event to synchronize a context across the firstelectronic device and the second electronic device.
 35. The method ofclaim 34, further comprising: receiving a subsequent context changeevent from the first electronic device; and informing the secondelectronic device of the subsequent context change event in response tothe second electronic device having a subscription to the subsequentcontext change event.
 36. The method of claim 34, further comprisingremoving the library to unsubscribe the first electronic device from theone or more context events.
 37. A system for facilitating context-basedspeech recognition, the system including one or more processorsexecuting one or more computer program modules which, when executed,cause the system to: access one or more contexts that are stored in acontext stack associated with a natural language utterance in responseto one or more grammars in a context description grammar failing tocorrespond to information associated with the natural languageutterance; compare the information to one or more context matchers todetermine a most likely context associated with the natural languageutterance; and use one or more grammar expression entries in the contextdescription grammar to generate a command or request associated with themost likely context.
 38. The system of claim 37, wherein the system iscaused to communicate the generated command or request to an agentconfigured to process the generated command or request in the mostlikely context and generate a response to the natural languageutterance.
 39. The system of claim 37, wherein the system is caused todetermine an intent or correct a recognition associated with the naturallanguage utterance based on the most likely context.
 40. The system ofclaim 37, wherein the system is caused to dynamically constrain avocabulary of words associated with a virtual dictation grammar toinclude one or more decoy words for out-of-vocabulary words based on oneor more prior utterances that were successfully transcribed by thespeech recognition engine.
 41. The system of claim 37, wherein thesystem is caused to use a dictation grammar or a virtual dictationgrammar to completely or partially transcribe the natural languageutterance.
 42. A method for facilitating context-based speechrecognition, the method being implemented in a computer system thatincludes one or more processors executing one or more computer programmodules which, when executed, perform the method, the method comprising:accessing one or more contexts that are stored in a context stackassociated with a natural language utterance in response to one or moregrammars in a context description grammar failing to correspond toinformation associated with the natural language utterance; comparingthe information to one or more context matchers to determine a mostlikely context associated with the natural language utterance; and usingone or more grammar expression entries in the context descriptiongrammar to generate a command or request associated with the most likelycontext.
 43. The method of claim 42, further comprising communicatingthe generated command or request to an agent configured to process thegenerated command or request in the most likely context and generate aresponse to the natural language utterance.
 44. The method of claim 42,further comprising determining an intent or correct a recognitionassociated with the natural language utterance based on the most likelycontext.
 45. The method of claim 42, further comprising dynamicallyconstraining a vocabulary of words associated with a virtual dictationgrammar to include one or more decoy words for out-of-vocabulary wordsbased on one or more prior utterances that were successfully transcribedby the speech recognition engine.
 46. The method of claim 42, furthercomprising using a dictation grammar or a virtual dictation grammar tocompletely or partially transcribe the natural language utterance.
 47. Asystem for facilitating speech recognition using dictation and/orvirtual dictation grammars, the system including one or more processorsexecuting one or more computer program modules which, when executed,cause the system to: receive a natural language utterance; andtranscribe the natural language utterance using a dictation grammar of aspeech recognition module or a virtual dictation grammar of the speechrecognition module based on whether a platform associated with thespeech recognition module has the dictation grammar available.
 48. Thesystem of claim 47, wherein the system is caused to dynamicallyconstrain a vocabulary of words associated with the virtual dictationgrammar to include one or more decoy words for out-of-vocabulary wordsbased on one or more prior utterances that the speech recognition modulesuccessfully transcribed.
 49. The system of claim 47, wherein the systemis caused to: identify a context matching a command or requestassociated with the transcribed natural language utterance; process, atan agent associated with the identified context, the command or requestto generate a response to the natural language utterance; and update, atthe agent, a context stack with information associated with theidentified context, the generated command or request, or the generatedresponse to enable one or more follow-up commands or requests associatedwith the identified context, the generated command or request, or thegenerated response.
 50. The system of claim 47, wherein transcribing thenatural language utterance comprises using the dictation grammar or thevirtual dictation grammar to completely or partially transcribe thenatural language utterance.
 51. A method for facilitating speechrecognition using dictation and/or virtual dictation grammars, themethod being implemented in a computer system that includes one or moreprocessors executing one or more computer program modules which, whenexecuted, perform the method, the method comprising: receiving a naturallanguage utterance; and transcribing the natural language utteranceusing a dictation grammar of a speech recognition module or a virtualdictation grammar of the speech recognition module based on whether aplatform associated with the speech recognition module has the dictationgrammar available.
 52. The method of claim 51, further comprisingdynamically constraining a vocabulary of words associated with thevirtual dictation grammar to include one or more decoy words forout-of-vocabulary words based on one or more prior utterances that thespeech recognition module successfully transcribed.
 53. The method ofclaim 51, further comprising: identifying a context matching a commandor request associated with the transcribed natural language utterance;processing, at an agent associated with the identified context, thecommand or request to generate a response to the natural languageutterance; and updating, at the agent, a context stack with informationassociated with the identified context, the generated command orrequest, or the generated response to enable one or more follow-upcommands or requests associated with the identified context, thegenerated command or request, or the generated response.
 54. The methodof claim 51, wherein transcribing the natural language utterancecomprises using the dictation grammar or the virtual dictation grammarto completely or partially transcribe the natural language utterance.